I receive multiple emails from Genius Scan

If you received multiple times the same email from Genius Scan, that means your email was stuck in theApple Mail app Outbox and the server tried to send it multiple times. When your email is stuck in the Outbox, the solution is to delete the email from your Outbox and try again.

Even if you are using a different app for your regular email, the issue here is with the Apple Mail app. This is the Apple Mail app:

Apple Mail won't let you delete the email from your Outbox while it's trying to send the email. The trick is to switch your device to Airplane Mode so that you can delete the email from the Outbox. Then force close the Apple Mail app (see instructions here: Force close an app), and try again.